DEVELOPMENT OF THE COASTAL BELT OF SOUTH AFRICA. 219 



above sea level. The Capetown Corporation had three rain 

 gauges about equally distributed over this area. The average 

 rainfall of these three gauges for the year 1903-1904 was 190 

 inches. Taking the rainfall for an average year at 150 inches 

 and a run-otit of 80 per cent, (careful measurements have shown 

 that the run-otf from Table Mountain is well over 80 per cent)^ 

 this gives a total run-off of 10,400 million gallons per annum, equal 

 to about 283/2 million gallons per day. This, falling 2,000 feet, 

 allowing 50 per cent, efficiency, would give about 6,000 BHP 

 per hour. If we take the value of this power at only ^d. per 

 BHP per hour, we get an annual value of well over £50,000 from 

 this small area. This area is at present drained by about 25 

 separate streams, falling over and rushing down the steep 

 mountain sides ; fthese would all have to be diverted — which 

 could be done, in most cases, by earth dams — and brought to one 

 central spot to be taken down over the sides of the mountain ; in 

 this case probably the waterfall would be the best spot. There 

 are many such areas in the Western Province. 



Irrigation. 



We must now leave the question of powej: and turn to our 

 second point, namely, irrigation. The coastal belt offers great 

 advantages for irrigation, over a wide and continuous area, and 

 with it intensive agricultural development, and closer settle- 

 ment. The following are some of the advantages that the 

 coastal belt offers for irrigation as compared with the dry 

 interior : — 



(i) Owing to the wide distribution of rainfall throughoiU 

 the year, a much shorter period of irrigation is required. 

 This is very important when water has to be pumped. 



(2) Owing to the long and heavy rainy season, the sub- 

 soil gets thoroughly wet, so that when irrigation is 

 required the depth of water required at each wetting is 

 much less. The author found that two or three inches 

 is sufficient for lucerne, as compared with six inches in 

 the Karoo. 



(3) Owing to the wide distribution of the rainfall during 

 the year, the storage capacity for irrigating a given area 

 of land is much less. 



(4) Through the poorness of the soil, there is a general 

 absence of conditions which produce brak. 



It may seem strange to claim the poorness of the soil as an 

 advantaee for the coastal region, but it is a matter of very great 

 importance. The Karoo lands are usually exceedingly fertile, 

 and, under irrigation, will produce their eight or nine crops of 

 lucerne a year, without manuring or fertilising. The coast lands, 

 are usually much poorer, and will usually only produce five or 

 six crops of lucerne a year, and then they often require 

 manuring. 



